Bicycle hub having enhanced strength

ABSTRACT

A hub for a bicycle includes a shaft, a hub body rotatably mounted on the shaft, a drive seat rotatably mounted on the shaft and engaged with the hub body, and a self-lubricating bearing mounted between the drive seat and the shaft. Thus, the self-lubricating bearing has an inner wall contacting with an outer wall of the shaft completely and an outer wall contacting with an inner wall of the drive seat completely, so that the external force applied on the self-lubricating bearing is distributed evenly and smoothly to prevent the self-lubricating bearing from being distorted or deformed due to a stress concentration, thereby enhancing the lifetime of the self-lubricating bearing.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a hub and, more particularly, to a hubfor a bicycle.

2. Description of the Related Art

A conventional ratchet hub for a bicycle in accordance with the priorart shown in FIGS. 6 and 7 comprises a shaft 10, a hub body 11 rotatablymounted on the shaft 10 and having an inside formed with a fixing recess110, a locking ring 111 secured in the fixing recess 110 of the hub body11 to drive and rotate the hub body 11 and having an inside formed witha plurality of oneway ratchet teeth 112, a drive seat 12 rotatablymounted on the shaft 10 and having an end face 120 extended into thelocking ring 111 and formed with a plurality of receiving slots 122, aplurality of pawl members (not shown) each pivotally mounted in therespective receiving slot 122 of the drive seat 12 and each meshing withthe oneway ratchet teeth 112 of the locking ring 111, and a plurality ofball bearings 14 mounted between the drive seat 12 and the shaft 10.

In assembly, the hub body 11 is connected to a wheel (not shown) of thebicycle, the shaft 10 is connected to a frame (not shown) of thebicycle, the drive seat 12 is connected to a freewheel 13 of thebicycle, and the freewheel 13 of the bicycle is driven by a chain (notshown) which is driven by a chainwheel (not shown) which is driven by apedal (not shown) that is pedalled by a rider.

In operation, when the freewheel 13 is rotated normally, the drive seat12 is rotated with the freewheel 13 to move the pawl members. At thistime, the pawl members are locked in the oneway ratchet teeth 112 of thelocking ring 111, so that the locking ring 111 is rotated by the driveseat 12 to rotate the hub body 11 which rotates the wheel. On thecontrary, when the freewheel 13 stops rotating or when the rotationspeed of the wheel is greater than that of the freewheel 13 (when thebicycle is moved on the downward slope), the rotation speed of thelocking ring 111 is greater than that of the drive seat 12, so that theoneway ratchet teeth 112 of the locking ring 111 press each of the pawlmembers. Thus, the drive seat 12 performs an idle rotation, so that thelocking ring 111 and the hub body 11 are not rotated by the drive seat12 and will not interfere with rotation of the drive seat 12. When therotation speed of the drive seat 12 (or the freewheel 13) is greaterthan that of the hub body 11 (or the wheel), the locking ring 111 andthe hub body 11 are rotated by the drive seat 12 again.

However, when an external force is applied on the hub due to a violenthit or jump, the external force applied on the hub is entirely supportedby the ball bearings 14 as shown in FIG. 7, so that the ball bearings 14are easily distorted or deformed due to a stress concentration, therebydecreasing the lifetime of the ball bearings 14. In addition, when theball bearings 14 are worn out or even broken, the shaft 10 is easilydamaged by the broken pieces of the ball bearings 14, thereby decreasingthe lifetime of the shaft 10. Further, each of the ball bearings 14 hasa larger size, so that the thickness of the hub cannot be changed freelyaccording to the practical requirement, thereby decreasing theversatility of the hub.

BRIEF SUMMARY OF THE INVENTION

In accordance with the present invention, there is provided a hub,comprising a shaft, a hub body rotatably mounted on the shaft, a driveseat rotatably mounted on the shaft and having a first end face engagedwith the hub body, and a self-lubricating bearing mounted between thedrive seat and the shaft.

The primary objective of the present invention is to provide a bicyclehub having a greater strength.

Another objective of the present invention is to provide a hub, whereinthe self-lubricating bearing has an inner wall contacting with an outerwall of the shaft or the bushing completely and an outer wall contactingwith an inner wall of the drive seat completely, so that the externalforce applied on the self-lubricating bearing is distributed evenly andsmoothly to prevent the self-lubricating bearing from being distorted ordeformed due to a stress concentration, thereby enhancing the lifetimeof the self-lubricating bearing.

A further objective of the present invention is to provide a hub,wherein the external force applied on the self-lubricating bearing isdistributed evenly and smoothly, so that the hub has a greater strengthand can withstand a greater stress.

A further objective of the present invention is to provide a hub,wherein the self-lubricating bearing has a thickness which is changedarbitrarily, so that the thickness of the hub can be changed freelyaccording to the practical requirement, thereby enhancing theversatility of the hub.

Further benefits and advantages of the present invention will becomeapparent after a careful reading of the detailed description withappropriate reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING(S)

FIG. 1 is a perspective view of a hub in accordance with the preferredembodiment of the present invention.

FIG. 2 is an exploded perspective view of the hub as shown in FIG. 1.

FIG. 3 is a plan cross-sectional view of the hub as shown in FIG. 1.

FIG. 4 is an exploded perspective view of a hub in accordance withanother preferred embodiment of the present invention.

FIG. 5 is a plan cross-sectional assembly view of the hub as shown inFIG. 4.

FIG. 6 is an exploded perspective view of a conventional hub inaccordance with the prior art.

FIG. 7 is a plan cross-sectional assembly view of the conventional hubas shown in FIG. 6.

DETAILED DESCRIPTION OF THE INVENTION

Referring to the drawings and initially to FIGS. 1-3, a hub for abicycle in accordance with the preferred embodiment of the presentinvention comprises a shaft 20, a hub body 30 rotatably mounted on theshaft 20 and having an inside formed with a fixing recess 300, a lockingring 31 secured in the fixing recess 300 of the hub body 30 to drive androtate the hub body 30 and having an inside formed with a plurality ofoneway ratchet teeth 310, a drive seat 40 rotatably mounted on the shaft20 and having a first end face 42 extended into the locking ring 31 andformed with a plurality of receiving slots 43, a plurality of pawlmembers (not shown) each pivotally mounted in the respective receivingslot 43 of the drive seat 40 and each meshing with the oneway ratchetteeth 310 of the locking ring 31, and a self-lubricating bearing 60mounted between the drive seat 40 and the shaft 20.

In the preferred embodiment of the present invention, the hub furthercomprises a bushing 70 mounted between the self-lubricating bearing 60and the shaft 20 to prevent the self-lubricating bearing 60 fromdirectly contacting with the shaft 20 made of metal.

The drive seat 40 has an inside formed with a mounting hole 41. Theself-lubricating bearing 60 is inserted into the mounting hole 41 of thedrive seat 40. The self-lubricating bearing 60 has a substantiallycylindrical shape and has a diameter corresponding to that of themounting hole 41 of the drive seat 40. The self-lubricating bearing 60has a length corresponding to that of the drive seat 40 and has an endportion formed with a radially and outwardly extending limit flange 62rested on a second end face 45 of the drive seat 40. Theself-lubricating bearing 60 has an inside formed with a mounting bore 61to allow passage of the shaft 20 and the bushing 70. Thus, theself-lubricating bearing 60 is rotatably mounted between the drive seat40 and the shaft 20 to reduce the rotation wear and resistance betweenthe drive seat 40 and the shaft 20 to the minimum.

In assembly, the hub body 30 is connected to a wheel (not shown) of thebicycle, the shaft 20 is connected to a frame (not shown) of thebicycle, the drive seat 40 is connected to a freewheel 50 of thebicycle, and the freewheel 50 of the bicycle is driven by a chain (notshown) which is driven by a chainwheel (not shown) which is driven by apedal (not shown) that is pedalled by a rider.

In operation, when the freewheel 50 is rotated normally, the drive seat40 is rotated with the freewheel 50 to move the pawl members. At thistime, the pawl members are locked in the oneway ratchet teeth 112 of thelocking ring 31, so that the locking ring 31 is rotated by the driveseat 40 to rotate the hub body 30 which rotates the wheel. On thecontrary, when the freewheel 50 stops rotating or when the rotationspeed of the wheel is greater than that of the freewheel 50 (when thebicycle is moved on the downward slope), the rotation speed of thelocking ring 31 is greater than that of the drive seat 40, so that theoneway ratchet teeth 112 of the locking ring 31 press each of the pawlmembers. Thus, the drive seat 40 performs an idle rotation, so that thelocking ring 31 and the hub body 30 are not rotated by the drive seat 40and will not interfere with rotation of the drive seat 40. When therotation speed of the drive seat 40 (or the freewheel 50) is greaterthan that of the hub body 30 (or the wheel), the locking ring 31 and thehub body 30 are rotated by the drive seat 40 again.

Accordingly, the self-lubricating bearing 60 has an inner wallcontacting with an outer wall of the shaft 20 or the bushing 70completely and an outer wall contacting with an inner wall of the driveseat 40 completely, so that the external force applied on theself-lubricating bearing 60 is distributed evenly and smoothly toprevent the self-lubricating bearing 60 from being distorted or deformeddue to a stress concentration, thereby enhancing the lifetime of theself-lubricating bearing 60. In addition, the external force applied onthe self-lubricating bearing 60 is distributed evenly and smoothly, sothat the hub has a greater strength and can withstand a greater stress.Further, the self-lubricating bearing 60 has a thickness which ischanged arbitrarily, so that the thickness of the hub can be changedfreely according to the practical requirement, thereby enhancing theversatility of the hub.

Referring to FIGS. 4 and 5, the hub further comprises a secondaryself-lubricating bearing 600 mounted between the drive seat 40 and theshaft 20 and juxtaposed to the self-lubricating bearing 60, and thebushing 70 is mounted between the secondary self-lubricating bearing 600and the shaft 20 to prevent the secondary self-lubricating bearing 600from directly contacting with the shaft 20 made of metal.

The secondary self-lubricating bearing 600 is inserted into the mountinghole 41 of the drive seat 40. The secondary self-lubricating bearing 600has a substantially cylindrical shape and has a diameter correspondingto that of the mounting hole 41 of the drive seat 40. Theself-lubricating bearing 60 and the secondary self-lubricating bearing600 have a total length corresponding to that of the drive seat 40. Thesecondary self-lubricating bearing 600 has an end portion formed with aradially and outwardly extending limit flange 620 rested on the firstend face 42 of the drive seat 40. The secondary self-lubricating bearing600 has an inside formed with a mounting bore 610 to allow passage ofthe shaft 20 and the bushing 70. Thus, the secondary self-lubricatingbearing 600 is rotatably mounted between the drive seat 40 and the shaft20 to reduce the rotation wear and resistance between the drive seat 40and the shaft 20 to the minimum.

Thus, the secondary self-lubricating bearing 600 has an inner wallcontacting with an outer wall of the shaft 20 or the bushing 70completely and an outer wall contacting with an inner wall of the driveseat 40 completely, so that the external force applied on the secondaryself-lubricating bearing 600 is distributed evenly and smoothly toprevent the secondary self-lubricating bearing 600 from being distortedor deformed due to a stress concentration, thereby enhancing thelifetime of the secondary self-lubricating bearing 600.

Although the invention has been explained in relation to its preferredembodiment(s) as mentioned above, it is to be understood that many otherpossible modifications and variations can be made without departing fromthe scope of the present invention. It is, therefore, contemplated thatthe appended claim or claims will cover such modifications andvariations that fall within the true scope of the invention.

1. A hub, comprising: a shaft; a hub body rotatably mounted on theshaft; a drive seat rotatably mounted on the shaft and having a firstend face engaged with the hub body; a self-lubricating bearing mountedbetween the drive seat and the shaft; wherein the self-lubricatingbearing has an end portion formed with a radially and outwardlyextending limit flange rested on a second end face of the drive seat;the limit flange of the self-lubricating bearing protrudes outwardlyfrom the second end face of the drive seat and abuts a periphery of thesecond end face of the drive seat.
 2. The hub in accordance with claim1, wherein the drive seat has an inside formed with a mounting hole, theself-lubricating bearing is inserted into the mounting hole of the driveseat, and the limit flange of the self-lubricating bearing protrudesoutwardly from the mounting hole of the drive seat.
 3. The hub inaccordance with claim 2, wherein the self-lubricating bearing has asubstantially stepped cylindrical shape.
 4. The hub in accordance withclaim 3, wherein the self-lubricating bearing has a diametercorresponding to that of the mounting hole of the drive seat.
 5. The hubin accordance with claim 1, wherein the self-lubricating bearing has alength corresponding to that of the drive seat.
 6. The hub in accordancewith claim 1, wherein the self-lubricating bearing has an inside formedwith a mounting bore to allow passage of the shaft.
 7. The hub inaccordance with claim 1, wherein the self-lubricating bearing isrotatably mounted between the drive seat and the shaft.
 8. The hub inaccordance with claim 1, further comprising a bushing mounted betweenthe self-lubricating bearing and the shaft, wherein the self-lubricatingbearing has a length equal to that of the bushing.
 9. The hub inaccordance with claim 8, wherein the self-lubricating bearing has aninside formed with a mounting bore to allow passage of the bushing. 10.The hub in accordance with claim 8, wherein the self-lubricating bearinghas an inner wall contacting with an outer wall of the bushingcompletely and an outer wall contacting with an inner wall of the driveseat completely.
 11. The hub in accordance with claim 1, furthercomprising a secondary self-lubricating bearing mounted between thedrive seat and the shaft and juxtaposed to the self-lubricating bearing.12. The hub in accordance with claim 11, wherein the drive seat has aninside formed with a mounting hole, and the secondary self-lubricatingbearing is inserted into the mounting hole of the drive seat.
 13. Thehub in accordance with claim 12, wherein the secondary self-lubricatingbearing has a substantially stepped cylindrical shape and has a diametercorresponding to that of the mounting hole of the drive seat.
 14. Thehub in accordance with claim 13, wherein the self-lubricating bearingand the secondary self-lubricating bearing have a total lengthcorresponding to that of the drive seat.
 15. The hub in accordance withclaim 13, wherein the secondary self-lubricating bearing has an endportion formed with a radially and outwardly extending limit flangerested on the first end face of the drive seat, and the limit flange ofthe secondary self-lubricating bearing protrudes outwardly from thefirst end face of the drive seat and abuts a periphery of the first endface of the drive seat, so that the drive seat is clamped between thelimit flange of the self-lubricating bearing and the limit flange of thesecondary self-lubricating bearing.
 16. The hub in accordance with claim11, wherein the secondary self-lubricating bearing has an inside formedwith a mounting bore to allow passage of the shaft.
 17. The hub inaccordance with claim 11, further comprising a bushing mounted betweenthe self-lubricating bearing, the secondary self-lubricating bearing andthe shaft, wherein the self-lubricating bearing and the secondaryself-lubricating bearing have a total length equal to that of thebushing.